3.2 Volcanic Activity


Vocabulary


Magma Chamber: A pocket that magma collects in beneath a volcano
Pipe: A long tube in the ground that connects magma chamber to the surface of the earth
Vent: An opening where molten rock+gas leave the volcano
Lava Flow: The area covered by lava as it flows out of a vent
Crater: Bowl-shaped bend in land that might form at the top of a volcano, around its central vent
Silica: A material formed from the elements silicon and oxygen
Pahoehoe: A fast/quick moving hot lava
Aa: A cool and slow moving lava
Active: Volcano that's erupting or is showing signals of erupting soon
Dormant: A sleeping volcano that is kind of like a sleeping bear
Extinct: A dead volcano, most likely won't erupt soon
Hot Spring: Forms when groundwater heated b a nearby body of magma rises to surface and collects in a natural pool
Geothermal Energy: Clean, dependable energy source given by water heated by magma

Outline


How Magma Reaches The Earth's Surface

  • Lava begins as magma in mantle
  • Magma forms in asthenosphere, which is under great pressure
Magma Rises
  • Liquid magma is less dense than surrounding solid material
    • So magma flows upwards into any cracks in rocks above until it reaches surface
      • It can also get trapped beneath layers of rock
A Volcanoe Erupts
  • Dissolved gases trapped in magma are under extreme pressure
    • Like carbon dioxide in soda bottle
  • As magma rises toward surface, pressure decreases.
    • Dissolved gases begin to seperate out, forming bubbles
  • Volcano erupts when an opening develops in the weak rock on surface
  • During volcanic erruption, gases rush out, carrying magma with them
    • Once magma reaches surface and becomes lava, gases bubble out

Inside A Volcano

  • All volcanoes have a pocket
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